Scientists have found that atmospheric carbon dioxide levels have increased from 280 parts per million over 400 parts per million during the last how many years

Answer 1

Atmospheric carbon dioxide levels have increased from around 280 parts per million (ppm) to over 400 ppm in the last approximately 150 years, primarily since the onset of the Industrial Revolution in the late 19th century. The significant rise in CO2 levels is mainly due to human activities such as fossil fuel combustion, deforestation, and various industrial processes.